Johnson steps in for Mumford & Sons at Bonnaroo

Johnson has agreed to take the Saturday night headlining slot at the Bonnaroo Music & Arts Festival after Mumford & Sons were forced to cancel.

Festival officials announced the move Friday morning. Johnson says he's "got a lot of lyrics and chords to relearn by Saturday night" in a statement. The singer of "Upside Down" last headlined at Bonnaroo in 2008.

Mumford & Sons' decision comes after bassist Ted Dwane received treatment this week for a blood clot on his brain. The band postponed three shows earlier this week after the blood clot was discovered but hoped to play Bonnaroo on Saturday night. Rather than perform with a replacement, the London-based folk rock band decided to pull out of Bonnaroo and two other performances, concluding its tour.